Question 1

___ is the pH at which an amino acid solution has no net charge because it has equal positive and negative charges.

Accepted Answer

The answer of ___ is the pH at which an...

Question 2

In which of the following levels of protein structure can hydrogen bonding NOT play a role?

Accepted Answer

A)   primary
B)   secondary
C)   tertiary
D)   quaternaryE) None of the above
F) A) and B)

Question 3

Given the following amino acids and their R groups:
glycine (R group is -H) - aspartic acid (R group is -CH2COO-)
cysteine (R group is -CH2SH) - lysine (R group is -(CH2)4NH3+)
Sketch cysteine.

Accepted Answer

Question 4

Noncompetitive inhibitors resemble the substrate and bond to the active site of an enzyme.

Accepted Answer

A) True 
 B)False

Question 5

The function of feedback inhibition is to

Accepted Answer

A)   affect the polarity of a substrate so that it will not be picked up by an enzyme.
B)   provide a stimulus to the enzyme that makes it active during a reaction.
C)   provide a way of keeping the wrong substrate from coming in contact with an enzyme.
D)   control an enzyme reaction so that there isn't an overproduction of the product.E) A) and D)
F) None of the above

Question 6

The hydrophobic portions of a protein tend to

Accepted Answer

A)   form chemical bonds between them so that the structure of the protein is rigid.
B)   be attracted to each other by means of strong interatomic forces.
C)   be strongly attracted to the water in the surroundings, pulling portions of the molecule away from its center.
D)   fold into the interior of the three-dimensional shape away from water.E) All of the above
F) A) and B)

Question 7

At physiological pH, most amino acids carry both a 1+ and 1- charge. This form is known as a ___.

Accepted Answer

A)   zwitterion
B)   anion
C)   cation
D)   isoelectric ionE) B) and C)
F) A) and D)

Question 8

Which of the following substances recognized by immune system evoke production of one or more antibodies?

Accepted Answer

A)   secondary proteins
B)   antigens
C)   globular proteins
D)   glycolipidsE) All of the above
F) A) and D)

Question 9

Protein molecules with the appropriate structure to be biologically active are native molecules.

Accepted Answer

A) True 
 B)False

Question 10

When a patient has accidentally ingested methanol, a physician can order the use of ethanol to overwhelm the alcohol dehydrogenase enzyme. This prevents the liver from producing deadly formaldehyde from the methanol. This is an example of _____.

Accepted Answer

A)   covalent modification
B)   feedback inhibition
C)   competitive inhibition
D)   protein denaturationE) A) and D)
F) B) and C)

Question 11

Which of the following sentences is true?

Accepted Answer

A)   Rearranging the amino acid residues in a peptide or protein changes its function.
B)   In an  α\alphaα -helix form, portions of polypeptide chain line up side by side with hydrogen bonds holding neighboring strands of sheet together.
C)   The order of amino acid residues in a protein is referred to as its tertiary structure.
D)   The overall three-dimensional shape of a protein is referred to as its primary structure. E) A) and C)
F) C) and D)

Question 12

The net charge of peptides and proteins affects their solubility.

Accepted Answer

A) True 
 B)False

Question 13

The oligopeptides have from 2 to ___ amino acid units in their molecules.

Accepted Answer

The answer of The oligopeptides have from 2 to ___...

Question 14

The term commonly used for a chain of amino acids 100 units long is ___.

Accepted Answer

A)   peptide
B)   oligopeptide
C)   polypeptide
D)   centapeptideE) None of the above
F) A) and C)

Question 15

Enzymes that display stereospecificity are those that will catalyze the reactions of both the L-form and the D-form of a carbohydrate.

Accepted Answer

A) True 
 B)False

Question 16

Explain whether or not both the inhibitor and the substrate can bind to the enzyme at the same time in competitive inhibition.

Accepted Answer

A competitive inhibitor compet...

Question 17

The ___ of a protein largely determines its secondary and tertiary structures.

Accepted Answer

The answer of The ___ of a protein largely determines...

Question 18

The enzyme known as alcohol dehydrogenase is capable of oxidizing ethanol, methanol and other hydroxyl group containing organic compounds into their corresponding aldehydes. Such an enzyme with ___ catalyzes the reaction of structurally related substances.

Accepted Answer

A)   absolute specificity
B)   relative specificity
C)   stereospecificity
D)   no specificityE) A) and D)
F) A) and B)

Question 19

Fibrous proteins, because of their long fibers, tend to be soluble in water.

Accepted Answer

A) True 
 B)False

Question 20

An inhibitor is a substance that affects an enzyme by

Accepted Answer

A)   reducing the ability to act as a catalyst.
B)   removing the prosthetic group from an enzyme.
C)   reacting with the enzyme so there is less effect of the chemical reaction's surroundings on the rate of reaction.
D)   stopping the separation of the enzyme from the product keeping the reaction from going to completion.E) A) and B)
F) A) and D)

Exam 12: Peptides, Proteins, and Enzymes

Which of the following sentences is true?

Correct AnswerverifiedShow Answer

The enzyme known as alcohol dehydrogenase is capable of oxidizing ethanol, methanol and other hydroxyl group containing organic compounds into their corresponding aldehydes. Such an enzyme with ___ catalyzes the reaction of structurally related substances.

Correct AnswerverifiedShow Answer

An inhibitor is a substance that affects an enzyme by

Correct AnswerverifiedShow Answer

The function of feedback inhibition is to

Correct AnswerverifiedShow Answer

Explain whether or not both the inhibitor and the substrate can bind to the enzyme at the same time in competitive inhibition.

Correct AnswerverifiedA competitive inhibitor compet...View AnswerShow Answer

In which of the following levels of protein structure can hydrogen bonding NOT play a role?

Correct AnswerverifiedShow Answer

Protein molecules with the appropriate structure to be biologically active are native molecules.

Correct AnswerverifiedShow Answer

The oligopeptides have from 2 to ___ amino acid units in their molecules.

Correct AnswerverifiedShow Answer

Which of the following substances recognized by immune system evoke production of one or more antibodies?

Correct AnswerverifiedShow Answer

When a patient has accidentally ingested methanol, a physician can order the use of ethanol to overwhelm the alcohol dehydrogenase enzyme. This prevents the liver from producing deadly formaldehyde from the methanol. This is an example of _____.

Correct AnswerverifiedShow Answer

Noncompetitive inhibitors resemble the substrate and bond to the active site of an enzyme.

Correct AnswerverifiedShow Answer

The term commonly used for a chain of amino acids 100 units long is ___.

Correct AnswerverifiedShow Answer

The net charge of peptides and proteins affects their solubility.

Correct AnswerverifiedShow Answer

___ is the pH at which an amino acid solution has no net charge because it has equal positive and negative charges.

Correct AnswerverifiedShow Answer

Given the following amino acids and their R groups: glycine (R group is -H) - aspartic acid (R group is -CH2COO-) cysteine (R group is -CH2SH) - lysine (R group is -(CH2)4NH3+) Sketch cysteine.

Correct AnswerverifiedShow Answer

Fibrous proteins, because of their long fibers, tend to be soluble in water.

Correct AnswerverifiedShow Answer

The ___ of a protein largely determines its secondary and tertiary structures.

Correct AnswerverifiedShow Answer

Enzymes that display stereospecificity are those that will catalyze the reactions of both the L-form and the D-form of a carbohydrate.

Correct AnswerverifiedShow Answer

The hydrophobic portions of a protein tend to

Correct AnswerverifiedShow Answer

At physiological pH, most amino acids carry both a 1+ and 1- charge. This form is known as a ___.

Correct AnswerverifiedShow Answer

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A competitive inhibitor compet...
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Given the following amino acids and their R groups: glycine (R group is -H) - aspartic acid (R group is -CH₂COO^-) cysteine (R group is -CH₂SH) - lysine (R group is -(CH₂)₄NH₃⁺) Sketch cysteine.

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